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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <div></div>
    <div></div>
    <div></div>

    <script>
        // 1. 数组的合并
        let arr = ['Vue', 'React'];
        // let result = ['ES6'].concat(arr);
        let result = ['ES6', ...arr, 'MySQL'];
        console.log('result: ', result); // ["ES6", "Vue", "React", "MySQL"]

        // 2. 数组的克隆（浅克隆）
        const data = ['J', 'A', 'V', 'A'];
        const copy = [...data];
        data.push['S'];
        console.log(copy);

        // 3. 伪数组变为真正的数组
        const item = document.querySelectorAll('div');
        console.log(Array.isArray(item));
        const items = [...item];
        console.log(Array.isArray(items));
    </script>
</body>
</html>